Not only a constituent material composed only of a metal material such as copper but also a composite material made of a metal and a non-metal inorganic material (representatively, ceramics), such as Al—SiC, have been made use of as a constituent material for a heat radiation member (a heat spreader) of a semiconductor element. Mainly aiming to achieve lighter weight of a heat radiation member, a composite material including magnesium (Mg) which is lighter in weight than aluminum (Al) or an alloy thereof as a base material has recently been studied (see Patent Document 1).
Patent Document 1 discloses successful manufacturing with good operability, a composite material excellent in thermal characteristics (high in thermal conductivity and small in difference in coefficient of thermal expansion from a semiconductor element or peripherals thereof) by arranging an aggregate of raw material SiC in a cast (a mold) and infiltrating the aggregate with a molten metal (magnesium) in that state.